Method for producing a packaging material

ABSTRACT

Press roll for a laminating machine for producing a packaging material which comprises a carcass layer consisting of paper or carton, and which carcass layer exhibits crease lines, through holes, openings or slits, which carcass layer exhibits, on one of its sides, a barrier layer, a plastic lining which is arranged outside the barrier layer, and film of laminant thermoplast which is arranged between the carcass layer and the barrier layer, with the press roll exhibiting a circular-cylindrical jacket surface having a facing consisting of an elastic material. According to the invention, the facing comprises sections in the jacket surface, which sections exhibit local deformation ability in relation to the surrounding facing. The invention also relates to a method for producing packaging material and to packaging material which has been produced using this method.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of co-pending U.S. application Ser. No.11/524,317 filed on Sep. 21, 2006, which is a Continuation of U.S.application Ser. No. 10/433,436 filed on Jun. 4, 2003, the entirecontents of both of which is incorporated by reference. This applicationclaims priority under 35 U.S.C. § 120 to U.S. application Ser. No.11/524,317 and U.S. application Ser. No. 10/433,436. U.S. applicationSer. No. 10/433,436 is a U.S. National Phase Application ofPCT/SE01/02779. Priority is also claimed under 35 U.S.C. § 119 toSwedish Patent Application No. 0004709-2 filed on Dec. 18, 2000.

FIELD 0F THE INVENTION

The present invention relates to a method for producing packagingmaterial which is in the form of a continuous laminate web and is of thetype which comprises a carcass layer made of paper or carton, one sideof which exhibits a layer which is arranged outside the carcass layerand which comprises, on the one hand, a barrier layer and, on the otherhand, a plastic lining which is arranged outside the barrier layer andwhich comprises one or more thermoplastic materials, with the carcasslayer being covered by the said layer along the whole of its surfacewhile the layer, along selected parts, extends beyond the edges of thecarcass layer. In the present instance, a barrier layer means a layerwhich first and foremost constitutes a barrier to oxygen. A preferredlayer consists of a metal foil layer, preferably an aluminum foil layer.

BACKGROUND OF THE INVENTION

Disposable packaging containers, particularly those for storing liquids,are frequently produced from a packaging material which consists of acarcass layer of paper, which layer is covered with thermoplasticmaterials and aluminum foil. The packaging material is frequentlysupplied in the form of webs which are reeled on storage reels andwhich, after having been unrolled from their storage reel, areconverted, by means of folding, into packaging containers in automaticpackaging machines. A commonly occurring packaging of this type is thatwhich is marketed under the trade name TETRA BRIK and which ispreferably used for liquid filling material of the milk, fruit juice,etc. type.

This packaging container is produced in automatic packaging and fillingmachines in such a way that the web which is unrolled from the storagereel is transformed into a tube by the edges of the web being joined inan overlap seam, after which the tube which has been formed is filledwith the intended filling material and subdivided into individualpackaging containers by means of repeated transverse seals, which arearranged at a distance from each other and at right angles to the tube.After the filling material which has been supplied has been enclosed inthis way in sealed-off parts of the tube, these parts are separated fromthe tube by means of cuts made in the said transverse sealing zones. Thesubdivided tube parts are then shaped, by means of folding along creaselines which are arranged in the packaging material, to form packagingcontainers of the desired shape, for example a parallelepiped shape.

Packagings of this type are frequently provided with opening notches inthe form of holes, openings or slits which are made in the packagingmaterial and which are covered with strips which can be torn off andwhich are normally termed “pull-tabs”. Alternatively the packagingdevice is provided with an external opening device, for example in theform of a plastic pouring spout having a screw top for resealing, whichopening device is only allowed to penetrate the packaging laminate inconnection with the packaging being opened and the product being used.In this connection, the packaging laminate is provided with an openingwhich consists of a punched-out hole in the carcass layer, over whichhole aluminum foil and thermoplastic layers have been laminated. Thus,when the filling material consists of a sterile product, such assterilized milk, or an acidic product, such as orange juice, thepackaging container is frequently manufactured from a packaging laminatecomprising an aluminum foil layer which makes the packaging extremelyimpervious to the penetration of gases, such as oxygen, which canoxidize the contents and impair its quality. In order to achieve thedesired imperviousness, it is very important that the aluminum foillayer is not broken or damaged during the shaping of the packaging orwhen the packaging material is being manufactured and, for the functionof the tear strip opening (the pull tab) or the penetrating openingdevice, it is of importance that the aluminum foil layer adheresextremely well to the area around the opening holes since otherwise theopening operation can easily fail. Thus when a covering strip has beenaffixed over the intended opening, this strip can be torn off inconnection with this operation, without, for all that, the inner liningof plastic and aluminum foil being torn open. When a penetrating openingdevice is used, this opening device can fail to make a clean cut in thealuminum foil and thermoplastic layer, resulting in frayed edges.

An object of the invention is, in a simple and effective manner, totreat and prepare a packaging material web of the abovementioned typesuch that the edge of the packaging material web is effectively sealedoff using an upper plastic film or a plastic film which is arrangedaround the edge zone. It is known to seal off liquid-absorbing materialedges, which are exposed to the inside of a packaging container, withbridging thermoplastic strips or thermoplastic strips which are foldedaround the edges. It is also known, for the same purpose, to provide thepackaging material web with what is termed a fixed plastic edge strip,i.e. with a plastic strip which projects from the edge of a carton weband which can be folded around the edge and sealed to its opposite side.Such a “fixed edge strip” is obtained by arranging carton webs alongsideeach other, such that they form a slit or gap between each other, afterwhich the webs and the slits are jointly covered with a plastic foil or,in certain cases, with a plastic foil and an aluminum foil, after whichthe covered webs are separated by means of a cut made in the slitregion, thereby forming a projecting, fixed strip. A drawback hashitherto been that it is not possible to obtain adherence, or it is atall events a poor adherence which is obtained, between, for example, analuminum foil layer and a plastic layer in the region of the slits sincethe aluminum foil and the plastic layer cannot be pressed togetherwithin the region of the cut and, in particular, not right up to theboundary edges of the slits due to the varying thickness of the materialand the resulting difficulty for the pressure rolls to compress thematerial within the slit region.

Packaging material of the type which is meant here can be produced bymeans of known technology, by applying the different layers, i.e. thealuminum foil layer, the inner plastic layer, etc., in several separatelamination operations, to the carcass layer consisting of paper orcarton, and such a lamination procedure works very well when the carcasslayer is not provided with holes, openings or slits, i.e. regions wherethe covering layers extend beyond or past edge zones of the carcasslayer. It has been found that, when an aluminum foil is being layeredonto a carcass layer web consisting of paper or carton, where thecarcass layer is provided with holes, openings or slits, difficultiesarise due to the fact that, in connection with the lamination, where thebinding laminating layer frequently consists of a thin extrudedthermoplastic film, the aluminum foil has to be pressed against thecarcass layer base using an press roll or soft pressure roll in order toachieve sufficient adherence between the aluminum foil layer and thecarcass layer. Since the aluminum foil layer is as a rule very thin(from approx. 5 to 10 μm), it comes to be pressed, by the press roll,against the edges around the opening or the slits in the carcass layerand partially pressed into the said holes or openings. Since theperforations have a relatively sharp edge, there is a risk of thealuminum foil rupturing and, at all events, the risk arises of thealuminum foil becoming creased around the edges of the openings or theslits and, as a result, either being weakened or achieving pooradherence with the carcass layer precisely in the edge zones of theholes or openings. Furthermore, the adherence between the plastic layerand the aluminum foil layer is poor in the region of the said holes orslits since the pressure of the press roll in the said regions islimited due to the reduction in the thickness of the material in thesaid holes or slits.

The abovementioned circumstances have constituted a severe problem whichhas firstly caused ruptures in the aluminum foil layer, and consequentlycaused the gas-tightness of the packagings to be inadequate, secondlycaused the opening function to be defective due to poor adherencebetween the aluminum foil layer and the carcass layer in the edge zonesaround the openings and thirdly caused poor adherence between thealuminum foil layer and the plastic layer along the parts where thealuminum foil layer and the plastic layer project outside the carcasslayer and are consequently not supported by this layer when beingpressed together.

The adherence between the aluminum foil layer and the film of laminantthermoplast which binds the aluminum foil layer to the carcass layer,and the adherence between the aluminum foil layer and the plastic liningwhich is arranged outside this layer (i.e. the plastic lining whichcomes to be in direct contact with the liquid which is to be stored inthe finished packaging) are especially critical. In the region of thesaid holes or slits, this adherence is frequently poor since thematerial exhibits a reduction in thickness in the holes or slits, whichreduction in thickness results in the pressure of the press nip beinglower at these sites. In other words, the reduction in thickness meansthat the press nip, comprising an press roll and a cooled roll, isunable to press the aluminum foil layer and the different polymer layerstogether sufficiently for achieving the requisite adherence inessentially the whole of the region defined by the hole or the slit,particularly in the vicinity of the hole edges. This is expressed as airinclusions adjacent to the edges of the hole or slit, which in turnmeans that problems of fracture formation in the aluminum foil arise,leading to impaired gas-tightness and consequently problems withasepsis. The air inclusions also result in it being difficult to tearoff or penetrate the membrane consisting of the aluminum foil and thepolymeric films in the hole/slit, with the ability to open the packagingbeing restricted and/or with it not being possible to make a clean cutwhen penetrating, resulting in the formation of frayed edges.

The difficulty of solving the problem of poor pressure in the press nipin the region of the holes/slits is aggravated by the fact that it is atthe same time necessary, in the press nip, to pay regard to optimizationaspects in relation to the adherence between the aluminum foil and thedifferent polymer layers in the regions outside the regions of theholes/slits. The polymeric layer which is to be laminated to thealuminum foil is extruded in molten or semi-molten form directly intothe press nip and has to be pressed together by the nip before thetemperature of the polymeric material falls too much, in connection withwhich the material solidifies. This means that the line load in the nipis only effective for laminating during the course of a first,relatively short, press nip length. A press nip length which exceedsthis effective press nip length only means that the line load isdistributed over a greater area, something which is a disadvantage sincethe pressure in the press nip then becomes lower. For this reason,conventional press rolls are manufactured with a homogeneous surfacefacing of relatively high hardness, normally greater than 80-90 Shore A,giving a short press nip length. However, this relatively hard,homogeneous surface facing results in the adherence in the regions ofthe holes/slits being poor, as previously discussed.

Another problem in connection with laminating a polymer film to acarcass layer consisting of paper or carton, which carcass layerexhibits through holes, openings or slits, is that the polymericmaterial tends to accumulate in connection with these holes, openings orslits.

Problems with adherence between the different layers in the laminate canalso arise in association with crease lines in the carcass layerconsisting of paper or carton, with these problems being similar tothose when holes, openings or slits are present.

SUMMARY OF THE INVENTION

The present invention aims to tackle the above complex of problems. Inparticular, the invention aims to offer an press roll which provides, inthe hole regions or crease line regions of the carcass layer, improvedadherence between the aluminum foil layer and one or more polymer layerswhich abut it, for example a plastic lining consisting of one or morethermoplastic materials and/or a film consisting of a laminantthermoplast, which layer(s) is/are extruded directly into a press nipwhich comprises the press roll in accordance with the invention. In thisconnection, the aim is that it should be possible to produce a press niphaving an advantageously short press nip length and optimized line loadat the same time as good adherence is achieved in the regions of theholes. Even in association with high line speeds, high line loads andshort press nip lengths, the press roll according to the inventionshould be arranged such that it has time to penetrate into the holeregions or crease lines to laminate together the films and layers whichare present at these locations.

These aims are achieved when use is made of the press roll according tothe invention as defined in Claim 1.

The invention also relates to a method for producing a packagingmaterial using the press roll according to the invention and to apackaging material which has been produced using the method.

The press roll comprises a metal core having a circular-cylindricaljacket surface, which jacket surface is faced with a facing consistingof an elastic material. According to the invention, the facing comprisessections which are located in the jacket surface and exhibit localdeformation ability in relation to the surrounding facing. In thispresent instance, the expression “local deformation ability” means thata deformation within such a section is only propagated to the facingmaterial outside of the section in question to a very limited extent ascompared with the deformation spreading which takes place in an entirelyhomogeneous jacket material.

According to a preferred embodiment of the invention, the sectionspossessing local deformation ability are arranged in a large number,with what is mainly a uniform distribution over the whole of the jacketsurface.

According to an alternative embodiment, the sections possessing localdeformation ability are arranged as, or in, one or more regions whichextend as cylindrical segments around the circumference of the roll inpositions which correspond to the holes, the openings, the slits or thecrease lines in the carcass layer of the packaging material. In thisconnection, each such segment can, in accordance with a first variant ofthis embodiment, constitute a homogeneous section having localdeformation ability, with the said sections/segments being fashionedfrom a first elastic, polymeric material exhibiting a first damping anda first E-module, and with the surrounding facing being fashioned from asecond elastic, polymeric material exhibiting a second damping and asecond E-module, such that the said first damping and said firstE-module are lower than the said second damping and said secondE-module, respectively. Alternatively, according to another variant ofthe embodiment, each such segment around the circumference of the rollcan comprise a large number of sections having local deformation abilityand being distributed mainly uniformly over the whole of each respectivesegment.

As a result of the sections having local deformation ability, a desiredpenetration into the hole regions or crease line regions in the carcasslayer is achieved when the carcass layer, the aluminum foil and thepolymeric layer(s) pass through the press nip at the same time as adesired pressure can be maintained in the press nip, with the line loadbeing retained, in the regions outside of the hole regions or creaseline regions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail below while referring tothe figures, of which:

FIG. 1 shows a diagram of a line for laminating packaging material,which line comprises two press nips at least one of which uses an pressroll in accordance with the invention,

FIG. 1 a shows a packaging material which results from the line in FIG.1, as seen in cross section,

FIG. 2 shows a section through the facing layer of an press rollaccording to the prior art, at a press nip against a cooling roll, witha packaging material having a hole in the carcass layer being located inthe press nip,

FIG. 3 shows an press roll in accordance with a first, preferredembodiment of the invention as seen from the side, and also a section ofthe facing of this roll at a press nip against a cooling roll, with apackaging material having a hole in the carcass layer being located inthe press nip,

FIG. 4 shows the press roll according to FIG. 3 as seen in perspectiveand with an enlargement of a region of the facing of the roll,

FIG. 5 shows, in perspective, how a majority of the sections possessingdeformation ability in FIG. 4 are able to be deformed locally at thesame time as a smaller fraction of these sections resists deformation,

FIG. 6 shows the same principle as in FIG. 5, as seen in a transversesection through an press roll in abutment against a cooling roll, in apress nip through which a packaging material having a hole in thecarcass layer is passing,

FIGS. 7 a-m show different variants of patterns in the facing, whichpatterns provide location deformation ability in the jacket surface,

FIG. 8 shows an press roll in accordance with a second embodiment of theinvention, as seen from the side, and a section of the facing of thisroll, at a press nip against a cooling roll, with a packaging materialhaving a hole in the carcass layer being located in the press nip.

DETAILED DESCRIPTION OF THE INVENTION

The line for producing a packaging laminate of the type which isreferred to here, which line is shown diagrammatically in FIG. 1,comprises a storage reel 20 containing a web 21 of fibre material, i.e.paper or carton, which, on one of its sides, can exhibit a thin coatingof a thermoplastic material, for example polyethylene. A storage reelcontaining a thin aluminum foil web 23 (5-20 μm) is designated 22 and anextruder for forming a film of molten laminant thermoplast 25(preferably polyethylene) is designated 24. A press roll 10, inaccordance with the invention, interacts, in a press nip 26, with acooling counter roll 41 having a steel surface in the laminating machinewhich is formed from these elements and also the extruder 24. From thisfirst laminating machine 10, 41, 24, the packaging laminate, which isnow semifinished, proceeds onwards to a second laminating machine whichcomprises a press nip 32, having a press roll 28 and a cooling counterroll 29, and an extruder 30, which can be arranged to co-extrude adouble-sided film 31 consisting of two different thermoplasticmaterials. In the second laminating machine 28, 29, 30, the semifinishedpackaging laminate which comes from the first laminating machine 10, 41,24 is laminated together with this double-sided film 31 on that side ofthe laminate which exhibits the aluminum foil. The double-sided filmcan, for example, comprise ethylene acrylic acid ester, EAA, which islaminated closest to the aluminum foil, and low density polyethylene,LDPE, on the outside of this. During operation of the lamination linewhich is shown in FIG. 1, the press roll 10 typically has a peripheralspeed of up to 800 m/min, preferably 300-700 m/min, and even morepreferably 400-700 m/min. The line load in the press nip 26 is typically20-60 N/mm, preferably 20-50 N/mm, and the press nip length is at least20 mm, preferably 20-35 mm, and even more preferably 20-30 mm. Thatwhich takes place in the press nip 26 as a result of the invention willbe described in more detail in connection with FIGS. 3-8.

FIG. 1 a shows the resulting packaging laminate from the line in FIG. 1as seen in cross section. The carcass layer 42 plus its initial coatinglayer (decor) 47 correspond to the web 21 in FIG. 1. The designations ofthe remaining layers are the same as for the webs/films which are shownin FIG. 1. FIG. 1 a also illustrates the problem of air inclusions 48,49, 50 in the packaging laminate, which air inclusions can be decreasedusing the present invention. The air inclusions 48, 49 on either side ofthe aluminum layer 23 are most critical for the function of the laminateand are those which the invention is principally intended to decrease.

FIG. 2 shows a section through a facing layer 40′ of a press roll inaccordance with the prior art, at a press nip against a cooling roll 41,with a packaging material 42 having a hole 43 in the carcass layer beinglocated in the press nip. The carcass layer 42, and consequently theside walls of the hole 43, typically exhibit a height (thickness) ofabout 0.2-0.5 mm. The hole 43 in the carcass layer can have any selectedform whatsoever and normally exhibits a largest dimension (diameter orlength) of at least about 10 mm and at most about 30 mm; however, it isalso possible to conceive of smaller holes, for example for drinkingstraws. As can be seen, problems arise in the region of the hole 43 dueto the fact that the facing layer 40′, which is homogeneous and of arelatively high degree of hardness, is unable to be deformed locallyaround the edges of the hole. The facing of the press roll is thereforeunable to satisfactorily penetrate down in the hole region in order toachieve perfect adherence between the different laminate layers whichare present in this region, thereby leading to the problems which havebeen described above.

FIG. 3 shows a preferred press roll according to the invention, whichroll is generally designated by 10. This roll typically exhibits anouter diameter of about 200-450 mm, in connection with which it should,however, be understood that the invention is not restricted to suchdiameters. While the core of the roll consists of a solid metal core,usually made of steel, it is naturally also possible to conceive of thiscore not being of a solid design. A facing 40 consisting of an elasticmaterial (seen in the section) is arranged on the circular-cylindricaljacket surface of the core. This facing 40 comprises sections 44possessing local deformation ability, in accordance with the invention.More specifically, these sections 44 possessing local deformationability are formed by a pattern in the jacket surface of the press roll10, i.e. in the outer part of its facing 40 but not right down to thecore of the roll. In this connection, each section 44 consists of a unitwhich is free standing/delimited from the remainder of the facingmaterial.

In the press nip, a certain number of sections/units 44 _(1-i), namelyas many as correspond to the area of the hole 43, can penetrate down inthe hole 43 in order, in the hole, to produce a pressure on thedifferent lining layers of the packaging laminate, against the coolingroll 41, which lining layers extend over the hole 43 in the carcasslayer 42 of the packaging laminate. The sections/units 44 _(>i) whichare located outside the area of the hole 43 are able, instead, to bedeformed locally such that a desired line load is achieved over theremaining areas of the packaging laminate. Between the sections 44,there are spaces 45 (shown clearly in FIG. 7) in which a void ispresent. Alternatively, the spaces 45 are filled with a compatiblematerial, for example foamed rubber, which provides good adhesion to thesections possessing local deformation ability. This filler materialexpediently exhibits a lower E module and damping than the material ofwhich the sections consist. Advantages of the spaces 45 being filledwith a filler material are that the risk of damage to the free standingsections is decreased and that it becomes easier to remove any moltenthermoplast which has happened to end up on the jacket surface afterpossible mishaps in the production.

In FIG. 3, the sections 44 are arranged in areas 33 which consist ofcylindrical segments around the circumference of the roll, with thepositions of the areas 33 corresponding to the positions of the holes inthe carcass layer of the packaging laminate when the carcass layer runsover the roll. However, it is also very definitely possible to conceiveof the sections 44 covering the whole, or essentially the whole, of thejacket surface with an essentially uniform distribution (not shown).

As a result of the jacket surface being profiled in this way,“deformation space” is created very locally. When the facing of the rollis deformed locally, the deformation will not be propagated in the sameway as in a conventional, homogeneous jacket facing but, instead, berestricted locally due to the voids between the sections being filled bysurrounding deformed sections or due to the filler material between thesections being compressed and breaking the force of the deformation ofthe sections. For this reason, it is possible to create largedeformations very locally in the jacket facing without the surroundingcontact surface being more than marginally affected.

FIG. 4 shows a press roll in accordance with FIG. 3 together with amagnified part of the facing material. FIG. 5 illustrates how a group offree standing sections 44 _(1-i) is able, in association with anotional, but not shown, hole in the carcass layer 42 of the packaginglaminate, to resist the deformation to which the surrounding sections 44_(>i) in the facing are subjected. FIG. 6 illustrates how the sections44 _(>i) are deformed in the areas around a hole 43 in the packaginglaminate while the sections 44 _(1-i) in the area of the hole 43 resistdeformation, as seen in a cross section through the press nip betweenthe press roll 10 and the cooling roll 41.

FIGS. 7 a-m show a number of different conceivable patterns in which thesections 44 are arranged. FIGS. 7 a-c illustrate how the sections canexhibit hexagonal cross sectional profiles, with the spaces 45 betweenthe sections in FIG. 7 a consisting of voids while the correspondingspaces in FIG. 7 b are filled with a compressible material. FIG. 7 cshows how the facing can comprise through holes 46 which preferablyextend right down to the core of the roll, which core is thenexpediently at negative pressure. FIGS. 7 d-f show corresponding typesof sections, with or without filler material and through holes, wherethe sections exhibit circular cross sectional profiles. FIGS. 7 g-h showhow the sections 44 can be arranged in a wave or zigzag pattern (withthrough holes 46 in FIG. 7 h), it being possible for the spaces 45between sections 44 to consist of voids or be filled with a fillermaterial. The same applies, in a corresponding manner, to the design inFIG. 7 i, which design corresponds to the cross section shown in FIG. 7j and shows a diamond pattern in which the sections 44 exhibitquadrangular cross sectional profiles. It is possible to conceive ofother alternative patterns, for example with the sections consisting ofelevated hemispheres, as is illustrated in the cross sections shown inFIG. 71 and 7 m, or pyramids, as is illustrated in the cross section inFIG. 7 k. It will be understood that it is also possible to conceive ofusing a number of geometries which are similar to those shown.

According to one aspect of the invention, the said sections 44 arearranged in a number amounting to 0.5-20 per cm, preferably 1-10 per cm,and even more preferably 3-6 per cm, in at least one extension directionin the jacket surface. Furthermore, the geometry should be such that anaggregate volume V_(se) of the sections 44 is related to an aggregatevolume V_(sp) of the said spaces 45 between the sections such that0.3*V_(sp)<V_(se)<10*V_(sp), preferably 0.5*V_(sp)<V_(se)<7*V_(sp), andeven more preferably V_(sp)<V_(se)<5*V_(sp). In this connection, anythrough holes 46 are not included in the volume V_(sp) of the spaces 45.In addition, a maximal height H of one of the said sections 44 should berelated to a distance L such that 0.2*L<H<3*L, preferably 0.3*L<H<2*L,and, even more preferably 0.5*L<H<1.5*L, where L is the shortestdistance between the bottoms of two spaces 45 on each respective side ofthe said section 44.

The advantage of also having through holes 46 in the facing 40 is thatthis creates an additional expansion space for the sections 44 when thelatter are deformed. If the core of the roll is additionally undernegative pressure and the through holes 46 extend right down in thecore, this then achieves an improved deaeration of the packaginglaminate, thereby preventing or decreasing air inclusions in thelaminate.

FIG. 8 shows yet another alternative embodiment of the invention inwhich each locally deformable section 44′ consists of an area or segmentwhich is essentially homogeneous both in a direction around thecircumference of the roll 10 and in an axial direction of the jacketsurface, preferably extending 3-15 cm in the axial direction. Thesesections 44′ are made up of a first elastic, polymeric materialexhibiting a first damping and a first E module whereas the surroundingfacing 40 is made up of a second elastic, polymeric material exhibitinga second damping and a second E module, with the said first damping andthe said first E module being lower than the said second damping and thesaid second E module, respectively. Preference is given to the sections44, consisting of insertions in the facing 40, which insertions exhibita thickness which constitutes 5-25%, preferably 7-20%, and even morepreferably 8-15%, of an aggregate thickness of the insertions 44′ plusthe facing 40, with the roll 10 preferably exhibiting, at these sections44′, a diameter which is greater than a diameter in association with thesurrounding facing, meaning that the section 44′ projects a shortdistance outside the surrounding jacket surface.

In addition to the improved ability of the press roll to penetrate downin holes, slits, openings or crease lines in the packaging laminate, anadvantage of the invention is that the nip force can be lowered inrelation to a conventional press roll for the purpose of achieving therequisite contact surface and local deformation. An advantage ofarranging the locally deformable sections in segments is that a highlocal deformation is achieved where this is required at the same time asthe rigidity of the conventional press roll is otherwise retained. Thismeans that, while the nip pressure is high in general, it is locallylower in association with the holes in the packaging laminate, where thedeformation is greater instead.

The invention is not limited by the above-described preferredembodiments. Thus, it should be understood, for example, that the pressroll according to the invention can equally well be used as the pressroll 28 in the second laminating machine in FIG. 11 in connection withwhich the press roll in the first laminating machine can be of the typeaccording to the invention or of a conventional type. It should also beunderstood that the press roll according to the invention can also beused in lamination lines in which the order in which the differentlayers of the packaging laminate are laminated together is different. Inbrief, it can be used when laminating packaging laminates which possessholes, slits, openings or crease lines in the carcass layer irrespectiveof the type of lamination line and irrespective of the order in whichthe different layers in the laminate are laminated together.

1. Method for producing packaging material comprising: delivering abarrier layer to a press nip between a press roll and a counter roll,the press roll comprising a metal core and an outer surface of elasticmaterial possessing sections which exhibit local deformation abilityrelative to a portion of the elastic material adjacent the sections;delivering a web of paper or carton to the press nip, the web comprisingcrease lines, through holes, openings or slits; delivering a thermoplastmaterial to the press nip so that the thermoplast material is betweenthe web and the barrier layer; pressing the thermoplast material, theweb and the barrier layer together in the press nip between the pressroll and the counter roll to deform at least some of the sections ofelastic material relative to adjacent portions of the elastic materialso that the elastic material of the press roll penetrates into thecrease lines, through holes, openings or slits in the web.
 2. Methodaccording to claim 1, wherein the counter roll is a cooling counterroll.
 3. Method according to claim 1, wherein the press roll exhibits aperipheral speed of up to 800 m/min.
 4. Method according to claim 1,wherein the press roll exhibits a peripheral speed of 300-700 m/min. 5.Method according to claim 1, wherein the press roll exhibits aperipheral speed of 400-700 m/min.
 6. Method according to claim 1,wherein the press nip exhibits a line load of 20-60 N/mm and a press niplength of at least 20 mm.
 7. Method according to claim 1, wherein thepress nip exhibits a line load of 20-50 N/mm and a press nip length ofat least 20 mm.
 8. Method according to claim 1, wherein the press nipexhibits a line load of 20-60 N/mm and a press nip length of 20-35 mm.9. Method according to claim 1, wherein the press nip exhibits a lineload of 20-60 N/mm and a press nip length of 20-30 mm.
 10. Methodaccording to claim 1, wherein the thermoplast material is delivered tothe press nip in a molten form.
 11. Method according to claim 1, whereinthe web of paper or carton delivered to the press nip comprises acoating of thermoplastic material on a surface of the web opposite asurface facing the barrier layer.
 12. Method according to claim 1,wherein the barrier layer delivered to the press nip is an aluminum foillayer.
 13. Method according to claim 1, wherein the sections arearranged in a quantity amounting to 1-10 per cm in at least oneextension direction of the outer surface.
 14. Method according to claim1, wherein the sections are arranged in a quantity amounting to 3-6 percm in at least one extension direction of the outer surface.
 15. Methodfor producing packaging material comprising: positioning a thermoplastmaterial, a web of paper or carton provided with crease lines, throughholes, openings or slits and possessing a first surface exhibiting acoating of thermoplastic material, and a barrier layer between a pressroll and an opposing counter roll, the press roll comprising a metalcore and a facing on the core comprised of elastic material; thethermoplast material, the web of paper or carton and the barrier layerbeing positioned between the press roll and the counter roll so that thethermoplast material is between the barrier layer and a second surfaceof the web that is opposite the first surface; and pressing together thethermoplast material, the web of paper or carton and the barrier layerbetween the press roll and the counter roll to adhere together thethermoplast material, the web of paper or carton and the barrier layer,and cause portions of the elastic material of the press roll to deformrelative to adjacent portions of the elastic material so that theadjacent portions penetrate into the crease lines, through holes,openings or slits in the web of paper or carton.
 16. Method according toclaim 15, wherein the barrier layer and the web of paper or carton aredelivered to between the press roll and the counter roll from respectivereels.
 17. Method according to claim 15, wherein the thermoplastmaterial is delivered to between the press roll and the counter roll ina molten form.
 18. Method according to claim 15, wherein the elasticmaterial is comprised of a plurality of sections each surrounded by aspace so that the sections of elastic material are deformable relativeto adjacent sections, the space surrounding each section comprising avoid or a compressible material having a lower E modulus than theelastic material comprising the sections.
 19. Method according to claim15, wherein the portions of the elastic material of the press rolldeform relative to adjacent portions of the elastic material by virtueof the elastic material being comprised of a plurality of sections eachlocally deformable relative to adjacent sections, the plurality ofsections being distributed over an outer surface of the press roll. 20.Method according to claim 15, wherein the portions of the elasticmaterial of the press roll deform relative to adjacent portions of theelastic material by virtue of the elastic material being comprised of aplurality of sections each locally deformable relative to adjacentsections, the plurality of sections being arranged to form at least onecylindrical segment extending around a circumference of the press roll.